Mumbles Posted October 30, 2009 Share Posted October 30, 2009 How large of jar are you trying to fill? Link to comment Share on other sites More sharing options...
due559 Posted October 30, 2009 Share Posted October 30, 2009 I'm trying to fill the Harbor Freight Rock tumbler jar, so i don't expect to use over 2 pounds of media. Link to comment Share on other sites More sharing options...
due559 Posted October 30, 2009 Share Posted October 30, 2009 Cool, thanx for the tips, i figured out that the rubber belt the rock tumbler came with was a POS so i ordered a clear urethane belt from pyrocreations.com, after receiving it i realized that they used the same stuff that you could buy much cheaper in footlong strips from McMaster-Car (also comes in green and orange). I didn't get the belting from McMaster-Car because i wouldn't know how to connect the ends to form a belt. Link to comment Share on other sites More sharing options...
firetech Posted October 30, 2009 Share Posted October 30, 2009 Due, I have 5lbs of .300" media I bought off ebay. It is the most efficient media I have ever used in those mills. 200g of bp in 4hrs. Link to comment Share on other sites More sharing options...
due559 Posted October 30, 2009 Share Posted October 30, 2009 Could you elaborate more on the media you got from ebay? Is it lead, stainless steel, or ceramic? So do you suggest a smaller diameter milling media increases efficiency in a small mill like mine? Link to comment Share on other sites More sharing options...
Mumbles Posted October 30, 2009 Share Posted October 30, 2009 I have actually heard that slightly smaller media maximizes efficiency. We are doing mostly grinding instead of large crushing. I've heard between 000 and .50 caliber is best for the size of mills we use. I've been trying to find it in bulk, but haven't been doing well with that. That is in regard to lead. Ceramic would potentially be too light, and I don't know about SS or copper/brass. Link to comment Share on other sites More sharing options...
due559 Posted October 31, 2009 Share Posted October 31, 2009 Wow, thats pretty interesting; I'm currently using .50 caliber lead-antimony balls so if I ever get my hands on smaller media I'll have to test it out. Link to comment Share on other sites More sharing options...
dagabu Posted October 31, 2009 Share Posted October 31, 2009 (edited) Thanx Mumbles, I've read something like that before - just trying to confirm it here. My original plan was to buy a hundred pieces of precut 1/2" x 3/4" 303 SS rod from speedymetals.com and use a bench grinder to remove the sharp edges by hand, not sure if that'll work though. Due, Don't remove the burrs, they break the comp down faster than the flats. Just use as is or if you are afraid of cutting your drum, fill it with kitty litter and let it run for a day. That will take the sharp edge down a little. BTW- I use three different sizes and types of media in my jars. It fills in all of the holes and grinds very fast. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...E:X:AAQ:US:1123 Good stuff D Edited October 31, 2009 by dagabu Link to comment Share on other sites More sharing options...
firetech Posted October 31, 2009 Share Posted October 31, 2009 Due, my media is lead. Here is a link to what I have.http://cgi.ebay.com/Sm-Lead-Balls-for-melt...=item23039f6b79 I highly recommend them. A friend of mine has the 3lb version and I have the 6lb. The drums are the same size so the 3 and 6 pound doesn't really matter but he uses .50 cal in his mill. Until I told him otherwise, and proved it, we thought his mill was efficient. Took 24 hrs for 100g bp. Now if you don't need that much bp and have the patience that's fine. However, I can put out 1200g in the same time he can put out 100g simply because of my media. Link to comment Share on other sites More sharing options...
dagabu Posted October 31, 2009 Share Posted October 31, 2009 (edited) Due, my media is lead. Here is a link to what I have.http://cgi.ebay.com/Sm-Lead-Balls-for-melt...=item23039f6b79 I highly recommend them. A friend of mine has the 3lb version and I have the 6lb. The drums are the same size so the 3 and 6 pound doesn't really matter but he uses .50 cal in his mill. Until I told him otherwise, and proved it, we thought his mill was efficient. Took 24 hrs for 100g bp. Now if you don't need that much bp and have the patience that's fine. However, I can put out 1200g in the same time he can put out 100g simply because of my media. Firetech, Lets not be spreading misinformation here. Small does not equate to faster grinding... ever. Most likely what you have is the height for efficient cascading of the media. As the media climbs the wall as the drum turns, it reached a certain height where it can no longer climb higher and cascades down and across the media heap. A charge of 1/2 of the jar by volume and 1/4 comp by volume sits almost exactly at the sweet spot for grinding. The 3.5# tumblers (I have used mine since the '80s) cannot efficiently cascade the media and take a long time to grind. It is tru that a smaller media diameter works in small tumblers but 1/2 x 3/4 lead filled copper tube cuts the grinding time down from 30 hours to 10. Yes, I do use .30 lead shot to fill the voids as you do but if you were to supplement this with larger and heavier media, you will find a better grind as well. The Spoonburg jar is one gallon and can grind 1# in 4 hours. Pic attached. Lets just keep away from the blanket statements about what works for everyone since it is just not true. Remember everyone, the secret is cascading, not tumbling. D Edited October 31, 2009 by dagabu Link to comment Share on other sites More sharing options...
jukka Posted January 26, 2010 Share Posted January 26, 2010 (edited) I still haven´t got clear picture on how to choose the optimal media size. My plan is to cast lead balls with little amount of (now I don´t have the English word for this) lead/tin/antimony mix to increase the hardness. My jars are 10cm and 20cm deep and have ID of 10,2cm.Those jars rotate at 55RPM atm. I tried to calculate the media OD dia with the formula from Mumbles in this topic, (265.45)/square root(jar ID-media ODdia) = (55RPM+35%) or something like this but I definitely didn´t get any realistic values, maybe due of the inch/cm conversations. So I would appreciate if someone could help me on this. (edit = media is not hollow so I meant diameter ) Edited January 26, 2010 by jukka Link to comment Share on other sites More sharing options...
angelluis Posted July 26, 2010 Share Posted July 26, 2010 The Mill A good idea for any moderately serious Pyro is to construct a device capable of turning coarse powders and compositions into much finer material. The most useful case for this is of course when manufacturing Black Powder. Black Powder that has been prepared via ball milling will always perform better than powder made with alternative preparation methods, such as using a coffee grinder or the CIA method. I have seen a lot of cases where people have chosen to purchase their ball mill, spending upwards of $20-$150 in the process. Though with a little research and improvisation it's extremely easy to build a high performance machine for a fraction of the price. Most of the materials are quite inexpensive and easy to obtain, I happened to build my mill with out spending a dollar in fact… The basic design of a mill consists of a Milling container filled with a milling medium, a drive shaft construct, a fly shaft/wheel construct and a motor capable enough to turn the heavy milling container. This is where the improvisation comes in; here is a picture of my mill to get things started: http://users.tpg.com.au/jholc/Ball%20Mill%20resize.jpg Although this image depicts the mill running inside, it should be stressed that when milling any material, the mill should be placed away from buildings, people, animals etc. These pictures were taken inside as it was convenient at the time of writing, and there is no material in the jar. Thanks Canadian_Pyro for pointing that out. As you can probably see, I have hardly taken the highly aesthetic route, but that's not exactly important, and I did want to say that I built it for nothing Scrap lumber was used, just some stuff that I found lying in my garden shed, to make the base and the uprights that hold drive shaft, it was put together with screws and is solid as a rock. The fly wheels are pivoting castor wheels that I had laying around unopened from a previous trip to the hardware store, they were inexpensive though, about $3 or so for both of them. They are rated at 20Kg each, which is more than enough for this application. The drive shaft is a stainless steel rod that I purged from an old printer I had, it came with the rubber grip already attached which was also very nice. The motor can be hard to find for free, although less difficult to find for a few dollars from a scrap yard, washing machine motors are ideal as they are powerful and quiet, which is what my motor was used for previously. My mate happened to have that lying around and gave it to me. I opted to use a direct drive system on the shaft to connect the motor. I rigged up a pseudo universal joint using garden hose and some hose clamps. It works a treat and will run smoothly even if the motor isn't perfectly aligned to the shaft. I didn't use any bearings because I didn't have any lying around, so I just placed the shaft directly through the wood and used some high quality bearing grease that I did have. I measured the area with an infra-red thermometer after several hours of use and there where no major hot spots. This is just one example and there are many other designs to be utilized depending on what materials you happen to have, you just have to remember the basic principles. Milling Jar & Media The milling jar is just the container that holds the composition and media during the milling process; it can be something as simple as a length of capped PVC pipe or cylindrical plastic container. Metal containers are not recommended, as they can spark during the violent rotation of the milling media and ignite the composition. The milling media is the material used to crush the composition or chemical inside the jar during its rotation. When making black powder, Lead media is preferred as it is completely non-sparking and heavy enough to create an efficient milling environment.Some Lead Milling Media: http://users.tpg.com.au/jholc/Milling%20Media%20resize.jpg It should be common sense but never mill friction sensitive compositions, such as flash powder. And if you are milling metals, you will need media that is made of stronger material than the material you are milling. Also when milling metals, you should open the jar and let new oxygen into the container every hour or so, as the rapid oxidisation of the newly exposed surface area can generate heat and ignite the metal. I hope this little write-up is helpful for those newbie's who are new to this. And it may be a good idea if people posted other examples of their mills, for design ideas. http://users.tpg.com.au/jholc/Ball%20Mill%20with%20jar.jpgHEY, I think this is great and you basically made this for pennies on the dollar . Very smart if you ask me,I just bought one from harbor frieghts for about $42.00 it's a 6lb 2 drum . Link to comment Share on other sites More sharing options...
SolarSeeker Posted February 23, 2011 Share Posted February 23, 2011 Ooh I didn't know I had 90% of the parts needed to make my own mill. The only thing I don't have is a good barrel,milling media, a proper belt,and hard labor. Link to comment Share on other sites More sharing options...
dagabu Posted February 23, 2011 Share Posted February 23, 2011 I sell all PVC jars for $40.00 shipped to the lower 48. (sorry AU and CA) http://www.pyrobin.com/files/jar_edited-1.jpg Link to comment Share on other sites More sharing options...
Algenco Posted February 23, 2011 Share Posted February 23, 2011 Dag, That's close to what just the parts cost here Link to comment Share on other sites More sharing options...
dagabu Posted February 23, 2011 Share Posted February 23, 2011 You are correct sir!! It costs $22.00 with tax for the parts, glue and paint, about $12.00 to ship them leaving me with about $6.00 in my pocket for all of my hard work. Bottom line, you need them, I make them, we are both happy Link to comment Share on other sites More sharing options...
Bonny Posted February 24, 2011 Share Posted February 24, 2011 I sell all PVC jars for $40.00 shipped to the lower 48. (sorry AU and CA) http://www.pyrobin.com/files/jar_edited-1.jpg I didn't want a red one anyway Link to comment Share on other sites More sharing options...
taiwanluthiers Posted June 9, 2012 Share Posted June 9, 2012 My sister gave me some cordless electric scrubbers that takes those Black and Decker Versapack batteries, and now I am just finding a use for them. I think I can turn it into a small ball mill. I want to keep my scale small because of high population density so I won't be milling more than 100-200 grams of stuff at one time. Think I can find a power supply (probably a computer power supply) and connect a dimmer switch between the motor and the power supply to control its rpm. Can someone fix the pictures for the original post? none of them are working. Link to comment Share on other sites More sharing options...
MondoMage Posted June 11, 2012 Share Posted June 11, 2012 You are correct sir!! It costs $22.00 with tax for the parts, glue and paint, about $12.00 to ship them leaving me with about $6.00 in my pocket for all of my hard work. Bottom line, you need them, I make them, we are both happy So can we order one in custom color, or just "stock" colors? And what colors are available, anyways? I'm thinking of building my own, but its looking to come out to be the darned close to the same price as ordering one. And, being inherently lazy at times, I will probably choose the easy route Link to comment Share on other sites More sharing options...
dagabu Posted June 11, 2012 Share Posted June 11, 2012 Plastics cost continue to rise in price so the jars are now $50.00 each shipped each. There are no stock colors, they are painted using Krylon Fusion for Plastic, the colors are HERE but any color outside Blue, Black, Red, Green and Orange will be an extra $2.00 for a single jar but no extra cost for two or more jars. There is no way to update the AGORA post so please email me with questions. -dag Link to comment Share on other sites More sharing options...
taiwanluthiers Posted June 19, 2012 Share Posted June 19, 2012 (edited) I am making one even though I don't plan on making more than 200g at a time. The reason is because rock tumblers do not exist in Taiwan, or at least I do not know the Chinese word for it to be of any help (google translate just spits out a really nonsense word). I won't do any 3 component milling (mill all 3 components together like what most people do) because it is impossible to find 100 feet of space away from any occupied structure. I will mill potassium nitrate with 1/3 of the charcoal it's supposed to have, then the rest with all the sulfur. As for the other guy who made a slow bp that left yellow residue, what charcoal did you use? It makes a big difference along with how you made the bp. Do NOT use charcoal briquettes because it contains a lot of other stuff. Edited June 19, 2012 by taiwanluthiers Link to comment Share on other sites More sharing options...
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